Our research program is an interdisciplinary approach to the study of brain-endocrine interactions employing the techniques of neuroanatomy, electrophysiology, neuropharmacology and immunoassay. The long-term goal is a deeper understanding of the mechanisms by which the central nervous system controls endocrine secretion and is, in turn, influenced by the secreted hormones. With a primary focus on the brain-pituitary-gonad axis and reproduction, sites and mechanisms of production, transport and action of central nervous transmitters, releasing factors, pituitary tropic hormones and gonadal and adrenal target organ steroids are under active investigation. The feedback actions of releasing factors, pituitary tropins and target organ hormones on endocrine secretion and behavior are of special interest. Neuroendocrine cyclic phenomena of various periodicities are being studied by a coordinated approach involving electrophysiological recordings and hormone assays with the hope of discovering the "Zeitgebers". Neuropharmacological, endocrine, and immunological methods of controlling fertility are also of major interest. Relations of the amygdala, hippocampus and other extrahypothalamic regions of the brain to the hypophysiotropic area (HTA) of the hypothalamus are being explored by methods of stereotaxic surgery, electrical stimulation and the antidromic identification of neurons. The antidromic technique will also be employed to identify HTA neurons projecting to the median eminence and will be combined with microiontophoresis and radioimmunoassay methods to study mechanisms by which the HTA controls adenohypophysial function. BIBLIOGRAPHIC REFERENCES: Baldwin, D.M., J.A. Colombo and C.H. Sawyer. Effects of limiting water intake on the rat estrous cycle with observations on LH, prolactin, and corticosterone. Proc. Soc. Exp. Biol. Med. 151:471-474, 1976. Carrer, H. and C.H. Sawyer. Changes in multiunit spike activity in the rat preoptic area induced by stimulating the midbrain. Exper. Neurol. 52:525-534, 1976.